α-substituted Phosphoryl Compounds (II). The Crystal and Molecular Structure of Diphenyl-[5,6-dichloro-1, 3-benzodioxol-(2)]-phosphine-oxide,C19H13O3PCl2

The compound crystallizes in the monoclinic space group P 2₁/c with four molecules per unit cell, and with the lattice parameters a = 11.807 Å, b = 13.070 Å, c = 11.312 Å, β = 96.74°. With X-ray diffraction data collected on a four circle diffractometer, the crystal structure has been determined by direct methods and refined to an R-value of 0.061 for 2735 measured and symmetrically independent reflections. The substance is a derivative of acetales of formyl diphenyl phosphine oxides. Correlations between the geometry of the structure and NMR-data are of interest.